Adding the skin layer of flesh coloured latex into the mould, and building the feet 'bones' with bolts in for tie downs, and flexible sole for greater movement possibilities. The extra sponge is to pad out the foot so that it won't be solid latex and should hopefully make it a bit easier to bend and move around:

Putting them in situation and pouring the latex in and around them, I'm guessing it's going to take the good part of a dry all the way through, possibly more, so I'll leave them there for now and move onto something else...